Representatives from the Grocery Manufacturers Association maintain that “the safety of both artificial and natural colors has been affirmed through extensive review.”

But CSPI’s Jacobson argues that many of the studies used to draw that conclusion were conducted by industry and are potentially biased. A 2010 CSPI report suggests that the three most commonly used dyes—Red 40, Yellow 5 and Yellow 6—are often contaminated with known carcinogens. The report also shines a light on animal studies that suggest some artificial colors promote tumor growth. Meanwhile, Blue 1, Red 40, Yellow 5 and Yellow 6 have all been shown to cause allergic reactions in sensitive populations.  Yellow 5—Tartrazine—has been shown to cause hives and asthma in as many as 26 percent of people with allergies.

Pediatrician Alan Greene, MD, says he too has concerns about behavioral and other impacts of dyes, and always steers kids away from them. But he sees an even more insidious impact of our ever-increasing appetite for artificially colored food.

“We are designed to be attracted to colorful foods so that we are led to ripe fruits and vegetables and other things that are good for us,” Greene says. “Food companies have learned that they can draw our attention away from those healthy foods by making unhealthy foods look colorful. We need to stop falling for it.”

Connect with writer Lisa Marshall at lisamarshall08@gmail.com.